Radio receiving apparatus



May 1. 1928.

A. A. KENT RADIO RECEIVING APPARATUS 2 Sheets-Sheet 1 Filed Jan. 4. 1926 l N VEN' TOR. P

{Wm $651M 1 ATTORNEY.

May 1, 1928.

A. A. KENT RADIO RECEIVING APPARATUS .Filed Jan. 4. 1926 2 Sheets-Sheet 2 a o I 0 6 1 m 0 9 c H I J L a n WW 1 u n m. 6 3 0 n 5 b 6 2 INVENTOR. a M m :4 m

1 ATTORNEY.

Patented May 1, 1928.

UNlTED STATES 1,668,155 PATENT OFFICE.

ARTHUR ATWATER KENT, OF ARDMORE, PENNSYLVANIA.

RADIO RECEIVING APPARATUS.

Application filed January My invention relates to radio receiving apparatus, and more partieularlyto structure for compactly mounting er arranging various elements and parts: of 1: receiving set.

In accordance with my invention, the movable elements of a plurality of'tuning devices, and particularly condensers, rotatably adjustable about parallel axes, are me.- ehanically coupled, for adjustment in unison by a single marmally operated knob or handle, by a band or belt, preferably in the form of a metallic ribbon, passing over and maintained in fixed relation'to'drums or pulleys secured to these-veral rotatable elements,

Further in accordance with my invention, the tuning devices are mounted upon a plate or panel on one side thereof, and the mechanical coupling for the rotatable elements of the tuning devices is disposed upon the opposite side of the platcor panel, bet-ween the latter and a wall of the cabinet or housing. all the bearings for the rotatable elements being supported by the plate orpanel, and the shafts of 'all the rotatable elements, except one. terminating short of the h0us in; wall, and said one extending freely through the housing wall tothe exterior thereof where there is 'attacheda handle or knob for control of all of the rotatableelement-s in'unison.

Further in accordance with my invention, a ledge member, preferably of metal, which carries elements or parts of the receiving set. has secured thereto the aforesaid plate or panel which carries the tuning elements and their mechanical coupling. and the ledge structure and plate or panel attached there? to constitute an inner panel structure re movable as a unit from the housing; and more particularly the ledge member may be secured to a wall. preferably of metal, of the housing which .witlrthe inner panel -structurc may be removed as a unit from the housing.

My invention resides in the features of structure, combination and arrangement of parts of the character hereinafter described and claimed. v

For an illustration of one of the. various forms my apparatus may take, reference is to be hadto the accon'ipanying drawings, In which:

Fig. 1 is a front elevational view of. a cabinet receiving set in accordance with my i nveution.

4, 1926. Serial No. 79.100.

Fig. 2 is a vertical sectional view, parts Ill elevation, taken on the line 2-2 of Fig. 3.

Fig. 3 is a horizontal sectional view, partly in plan, on the line 3-3 of Fig. 1.

Fig. 4 is a vertical sectionalview, partly in elevation, taken'on the line 4-4 of Fig; 2.

Fig. 5 is a vertical sectional view, partly in elevation, taken on the line 5-5 of Fig. 2. Fig. 6 is ,a fragmentar horiiontal sectional view, partly in' p an,, on enlarged scale, taken on theline 66 of Fig. 2.

' Fig. 7 is afragmentaryelevational view, partly in section, of a part/of the mechanical coupling means.

Fig. 8 is anelevational view of a part of one of the condensers.

Fig. 9 is a diagrammatic view of one of various forms of radio receiving circuits of a character to which my invention is particularly adaptable.

Referring to the'drawings, 1 is the bottom of a cabinet. housing or box of wood or any other suitable material, having the back 2, ends 3, 3, top member '4'attached to the ends 3, .3, andthe cover or top 5. hinged to the back 2 at'6 The.plate' or panel P, of any suitable insulating. or condu'cting material, but preferably of iron, steel, aluminum or brass. is securedby screws 7 to the cabi net or housing, and. constitutes the front wall or panel'thereof. Securedto thepanel P adjacent and substantially parallel to its lower edge is the shelf or ledge member L, preferably of sheet'metal, having the integral flange 8 spot-welded or otherwise secured to the panel P. v

Spaced from and disposed substantially parallel with the front panel P is ,the plate or panel. O. preferably carried by or secured to panel P Preferably, and as indicated, the panel 0 is secured to the panel P by attachment to the ledge or shelf member L. For this purpose the panel 0 has at its lower edge the inwardly turned integral flangeosecured by screws 9 or equivalent meansto the member L.

Upon the panelO aremounted several variable adjustable tuning devices, such as variable inductances, or. and preferably, as indicated, variable tuning condensers for tuning two or more circuits 'of the receiving set.

In the example illustrated,.three variable condensers 0,0 and C are mounted upon the panel 0 and have their rotors or adjustable elements mechanically coupled for simultaneous adjustment in unison by a single knob or handle on the outer side of the front wall or panel P.

In the example illustrated, each condenser comprises the end plates 10 and 11, of: molded insulating material, secured to and spaced from each other by the metal posts 12. The front plates 10 of the several condensers are secured to the panel 0 by screws or bolts 13. The screws 13 securing the plate 10 of the middle condenser to the panel 0 have threaded thereon the long nuts or spacer members 13 abutting against the rear face of the panel P through which extend screws 13 threading'into the members 13. This structure forms a further connection. between the panels 0 and .P serving to stiffen both of them. and to holdthe panels 0 and P in definite position with respect to each other. The stator plates-14 of each condenser are carried by two of the posts 12, and there interleavewith the stator plates the-rotor plates 15 carried, in the several condensers, by the-rotor shafts 1G, 17 and 18, respectively. Eachfof the rotor shaftsis mounted in bearings carried by the end plates 10 and 11, and each rotor may be provided with a counterbalance weight 19.

The rotor shafts extend freely through apertures 20in the panel 0. The shafts 16 and 18. of the condensers C and C terminate in the space between the panels 0 and. P, while the shaft 17 of the'condenser G extends freely .through anaperture 21in the front panel P to the front side thereof, where there is. attached thereto the operators knob or handle 22, with which may be associated adial 23 hearing suitable graduations co acting with the marker .or index 24 on the panel P, Fig. 1.

Secured upon the rotor shaft 17 between panels 0 and Pisthe. drum or. pulley 25 of any suitable insulating. or conducting material, as occasion may require. In the example illustrated, the pulley 25 is of metal secured to the shaft 17 by the set screw 26. Secured by .set screws 27 upon the shafts 16 and 18, respectively, are .the similar drums orpulleys 28. and 29 disposed between panels 0 and P.

. Passing over the pulleys or drums 28 and 25 is the .belt .or band 30, and passing over the pulleys or drums 25 and 29 is the belt or band 31. The members 30 and 31. may he of any suitable material, metallic or otherwise; in the example illustrated they areribhons of brass, phosphor bronze or the like. V 7

To ensure that the several rotors of the different condensers be maintained always in the same angular. positions with respect to each other, throughout their adjustments, there are provided means for preventing creeping or slippage of the bands or belts 30 and 31 with respect to the pulleys with 32 and 33 will not rotate more than 180 degrees, this being the maximum angle through which the rotors are adjustable and the angle within which the markings upon the dial 23 are disposed.

For effecting nice or fine adjustment of the several rotors there may be carried upon the fro nt panel P' a rotatable button-34, which may be pressed into engagement with the dial 23 and manually rotated to rotate the dial 23 and therefore the several coudcnseivrotors through an angle smaller than the angle of rotation of theknob 34.

Suitable stops may be provided for limiting the extent of rotation of the condenser rotors. In the example illustrated the stops 35 and 36, Figs. 3, 5 and 8, of rubber or other suitable material, are carried by the plate 11 of the condenser C and are so positioned that the ends 19 and 19" of the counterweight 19 engage the stops 35aud upon counter-clockwise and clockwise rotations, respectively, of the shaft 17, as viewedin Figs. 8 and 3. The stops 35 and 36 are so positioned that, with regard to the angular extent of, the counterweight member-19, the extentof angular adjustment of the rotors is preferably v180 de rees, and in any event, such that pins and 33, extending through the bands 30 and 31 may not be rotated through more than 180 degrees.

The apparatus described may be utilized in connection with radio receiving systems of various types, and particularly of the type in which by a single manual control several tunable circuits are simultaneously tuned.

The apparatus described is suitable for a system such as illustrated in Fig. 9, in which V and V are radio frequency thermionic amplifiers of the audion type, each colnprising as usual an anode a, grid 9 and cathode or filament f. The input or grid circuit of the tube V includes the secondary coil of a radio frequency step-up transformer T, the input circuit being tunable by the variabl condenser C to the various wave lengths lying within the range of wave lengths for which the set or system is designed. The output circuit of the tube V is coupled by the radio frequency step-up llu) Ill)

transformer 'l. to the input circuit of the tube V similarly tunable tor the same wave length range by the variable condenser C. In the grid leads of the tubes V and V may be included resistances 'r of av magnitude to prevent substantial regeneration or production of oscillations, it being understood that any other suitable arrangement; for like nu'posc may be utilized. The output circuit of the tube V is coupled by the radio frequency step-up transformer T to the input circuit'o't the detector tube V similarly tunable throughout the same wave length range by the variable condenser C. In the grid lead of the tube V is the usual grid condenser C, and there may be provided a grid leak resistance r.

The several tuned or tunable systems or circuits include similar inductan'ces and eapacities. In the example described, the adjustable tuning devices are'the condensers C, C and C and they are similar to each other in the sense that they eflfct substantially equal changes in capacity when their rotors or adjustable elements are moved or adjusted through the same angular extents. There may be utilized variable condensers of any suitable characteristic as regards change of capacity with change of position of the rotor. A type particularly suitable for use for the purposes describedis such as illustrated and'of which it is characteristic that for equal increments of angular adjustment of the rotor the-capacity increases with substantially equal increments; that is, the increments of capacity are equal for equal angular displacements or increments of adjustment of the rotor. Y

The output cricuit of the detector'V is coupled by an audio frequency transformer T whose primary may be shunted by the radio-frequencyby-pass condenser C", with the input circuit of the audio frequency amplifier V whose output circuit is coupled by the audio frequency transformer T with the input circuit of the audio frequency amplifier V in whose output circuit is the signal-transmitting instrument I, such as a loud speaker, telephone or the like.

To ensure thatthe rotors ofthe condensers C, C, C may all be moved in unison to similar and proper settings to tune to eaclr of the various wave lengths, and thereby enable the operator to simultaneously tune the three circuits by manipulation of the knob 22 and dial 233, there is interposed between the first radio frequency amplifier tube V.'\ vh'ose input circuit is tuned by the condenser C, and the antenna or similar open absorption path D a radio frequency amplifier tube V, whose output circuit is coupled by the radio frequency transformer T to the tunable in at circuit of the tube V. The first tunab e systemor circuit with which is associated the tuning condenser (l is not nuiterially influenced as regards its tuning characteristics by the antenna or open absorption path, and, therefore. with similar tuning devices and condensers in and for the successive tunable systems or circuits, they may be tuned to the several different wave lengths by substantially similar and equal extents of movement of the rotors or adjustable elements, which, because of their mechanical.coupling above described, may be effected by the single handle or knob 22.

In series between the antenna or other absorption path D and earth or counter-capacity E is the primary p of a radio frequency auto-transformer F, the terminals of. whore secondary s are connected to the grid and cathode of the tube V.

The antenna or open absorption path and the input circuit of the tube V constitute, in effect, a single input system which; is not tunable to the separate various wave lengths to be received by the set. The inductance and capacity of the input system are not varied or adjusted, and such inherent variation as may occur in inductance'and capacity due to changes in wave lengthsdoes not affect the first tunable circuit or system with which is associated the condenser C.

In the antenna or openabsorption path may be utilized a resistance r The anode circuits of the several vacuun'i tubes are supplied by the source B, low voltage preferably'f being impressed upon the anode circuit of the detector V I intermediate voltage upon the'an'ode circuits of the tubes V, V and high voltage upon the anode circuits at the tiibesV} and-v The cathodes or filaments are heated as usual b current from the source A.

On tie front of the panel P is secured a structure R comprising arheostat 'r, Fig. 9, adjustable by the knob or handle 37 common to and controlling the current delivered from the source A tothe filaments f of the tubes V, V and V and a second rheostat 1", Fig, 9, adjustable by the knob or handle 38 common to and in the circuit of the filaments of the tubes V, V and V Of the parts of the receiving apparatus above described in connection with Fig. 9, the condensers C,'C and 'C are, as previously stated, mounted upon the panel 0. Supported upon these condensers, and therefore upon the panel'OQare the radio frequency transformers T, T and T The tube sockets 39, 4-0 and 41., for the tubes V, V and V respectively, are carried upon insulating bases or brackets 42 secured upon the ledge L adjacent its inner edge. The sockets 43, 44 and 45, for the tubes V, V and V, respectively, are carried upon the member 46 of insulating material secured upon the ledge L at-its inner edge. The audio frequency transformers 'T" and T are carried by the member 4-6. The auto transformer F is supported upon the ledge L, as indicated in Figs. 2 and 3.

The several rotors of the condensers C, O and C are preferably directly or indirectly connected to the panel P, when of metal, or lo the ledge L or the second panel O. The rotors are preferably grounded, and this may be effected by a separate connection to ground, but preferably also, as stated, by connection to the plate 1 or O, which may be grounded.

Bystructure of the character herein described, the several rotors of the tuning devices, and more particularly condensers,are adjustable in unison by a single manual control; and the mechanical coupling means are disposed between the two panels, with. the operating handle or knob on the outside of the second panel. 1 1

Furthermore, by loosening the panel P from the housing, the radio receiving.apparatus may be removed-as aunit, since. all the elements or parts are carried by the. panel P and some of them, as the tuning eondensers or equivalents, are carried indirectly by the panel P because of their attachment to the panel 0.

While the condenser structures have been herein described as separate condenser units separately or independently attached to the panel 0, it will be understood thatthe panel 0 may be common to and be comprised in each condenser unit, by n1ounting the rotor and stator elements of each condenser upon the panel 0 independently of each other, whereby the panel 0 is comprehended or. included in each condenser unit, as describedin my prior Letters PatentNo. 1,562,826, April-27, 1926. 1

What I claim-is:

1. Radio receiving apparatus comprising a plurality of tuning devices having adjustable elements rotatable about parallel axes, drums secured to said elements, a band coupling said drums to effect adjustment of said elements in unison, said band having an-aperture for each of said drums, and a member carried by each of .said drums closely fitting in one of said band apertures to maintain said rotatably adjustable elements in fixed angular relation to each other throughout their movements in both directions.

2. Radio receiving apparatus comprising a plurality of tuning devices havin adj ustable elements rotatable about paral lel axes, drums secured to said elements, a band coupling said drums to effect adjustment of said elements in unison, said band having an ap-.

erture for each of said drums, a member carried by each of said drums engaging in one of said band apertures to maintain said rotatably adjustable elements in predetermined angular relation to each other, and stop structure limiting rotation of said drums to an extent preventing withdrawal of said members from said apertures.

3. Radio receiving apparatus comprising a plurality of tuning devices having adj ustable elements rotatable about parallel axes and constitut-ii'ig the sole means for tuning a plurality of cascaded circuits, drums secured to said elements, a band coupling said drums to eifect'adjustment.of said elements in unison, said band having an aperture for each of said drums, a member carried by each of said .drumsclosely fitting in one of said band aperturesto maintain said rotatably adjustable elements in fixed angular relation to each-other in both directions of movement, and stop structure co-acting-With one of said rotatable elements to limit the extentof ro tation of said-rotatable elements and limiting rotationzofsaid. drums to prevent withdrawalofi said members fronrsaid apertures. 4. Radio receiving apparatus comprising a plurality. of tuning devices-having adjustableelements rotatable about parallel axes, drums secured to said elements, bands coupling one of saiddrumsto .the other drums,

.means .preventingslipping of said bands upon said drums,-aud .stop structure limiting the rotation of one of said drums and through said-bands the other drums to an extent. maintaining operative said slip-pie vcntiug means. i

5. Radio receiving apparatus comprising a housing, a panel constituting a detachable wall of said housing,'a ledge member secured to the inner side of said panel at -a right angle thereto, a second panel secured to said ledge member andspaced from ,said first named panel parallel thereto, a plurality of tuning devices carried byv saidsecond panel on theside thereof opposite to said first named panel and-having adjustable elements rotatable aboutparallel axes, means disposed between said panels mechanically coupling said rotatable elements to effect their adj ustment in unison, and elements of a receiving set carried by said ledge member indcpend ently of said second panel.

6. Radio receiving apparatuscomprising a housing, :a panel constituting adetachable wall of said housing, a member-secured to the inner side of said panel, a second panel secured to said member and spaced from said first namedpaneha plurality of tuning de vices carried by said second panel on the side thereof opposite-to said first named panel and having adjustable elements rotatable about parallel axes, means disposed between said panels mechanically coupling said re tatable elements to effect their adjustn'ient in unison, all the bearings of said adjustable elements carried by said second panel, and additional elements of. the receiving apparatus carried by said member.

. 7. Radio receiving apparatus comprising a housing, a member secured to the inner side ESU of a wall of said housin a panel secured to said member and space from said wall in substantially parallel relation, a plurality of condensers ea-rried by saidpanel on the side thereof opposite said .wall and having rotors with axesparallel to each other, means between said panel and wall mechanically coupling said rotors, and additional elements of receivin apparatus carried by said member independently of said panel.

8. Radio receiving apparatus comprising a plurality of tuning devices having rotatably adjustable elements, drums connected to said elements, a band coupling said drums to effect adjustment of said elements and comprising with said drums and said elements a movable system, said band having an aperture for each of said drums, a mem ber carried by each of said drums engaging in one of said band apertures to maintain said rotatably adjustable elements in predetermined angular relation to each other, and stop structure co-acting with an element of said movable system to-tlimit the. extent of rotation of said ustable elements and limiting rotation of said drums to an extent preventing withdrawal of said members from said apertures.

9. Radio receiving apparatus comprising a housing, panel structure therein having a portion spaced from a wall of said housing, vacuum tube holders, inductive devices and variable tuning condensers carried by said panel structure, and removable therewith as a unit from said housing, said condensers comprising rotor shafts all of whose bearings are carried by said panel structure, drums secured to said shafts between said housing wall and said portion of said panel structure, a band coupling said drums, all of said shafts but; one terminating short of said housing wall said one of said shafts extending freely through said housing wall to the exterior thereof, and manually opera-ble means exterior to said housing secured to said last named shaft for effecting adjustment of the condenser rotors in unison.

10. Radio receiving apparatus comprising aplurality of tuning devices having rotors whose axes are parallel, drums secured to said rotors, a metal band coupling said drums to effect adjustment of said rotors in unison, means for maintaining fixed the angular position of said rotors with respect to each other throughout their tuning adjustments in either direction comprising means maintaining a point in each drum-engaging portion of said band in fixed relation to a point on each of said drums, and stop structure associated with one only of said drums limit its rotation in both directions and throu said band limiting the rotation in both irections of the other drum.

lLRadio receiving apparatus comprising a plurality of tuning devices having rotors whose axes are parallel, drums secured to said rotors, a band coupling said drums to etl'ect adjustment of said rotors in unison, and means for n'iaintaining fixed the angular position of said rotors with respect to each other in their tuning adjustments in either direction comprising with respect to each drum and said band an aperture in one of them and a member on the other closely fitting said aperture.

12, Radio receiving apparatus comprising a plurality of tuning devices having rotors whose axes are parallel, drums secured to said rotors, a band coupling said drums to effect adjustment of said rotors in unison, means for maintaining fixed the angular position of said rotors with respect to each other throughout their tuning adjustments in either direction comprising means maintaining a point in each drum-engaging portion of said band in fixed relation to a point on each of said drums, and stop structure associated with one only of said drums limiting the rotation of said drums to a range within which said points maintain their fixed relation to each other.

13. The combination with condensers having rotor elements, of drums secured thereto, a band of conducting material mechanically coupling said drums, and a conductive connection between said rotor elements including said band.

14. The combination with condensers having rotor elements, of drums of conducting material secured to the rotor elements and electrically connected therewith, and a conducting baud mechanically coupling and electrically connecting said drums.

15. Radio receiving apparatus comprising a plurality of tuning condensers having rotors whose axes are parallel, drums secured to said rotors, a band coupling said drums to eli'ect adjustment of said rotors in unison, means for maintaining fixed the angular position of said rotors with respect to each other throughout their tuning adjustments in either direction, and stop structure associated with the rotor of one of said condensers only to limit its angular adjustment and through its drum and the band coupling with another of said rotors limiting the rotation ofsaid other rotor.

16. Radio receiving apparatus comprising a phirality of tuning condensers having rotors whose axes are parallel, drums secured to said rotors, a band coupling said drums to effect adjustment, of said rotors in unison, said band having an aperture for each of said drums, a member carried by each of said drums closely fitting in a band aperture to maintain said rotatably adjustable rotors in fixed angular relation to each other throughout their movements in either direction, and stop structure associated with the rotor of one of said condensers onlv for limiting its rotation and through its drum and said band limiting the rotation of the rotor of another of said condensers.

17. Radio receiving apparatus comprising a plurality of tuning condensers having rotors whose axes are parallel, drums secured to said rotors, a band coupling said drums to effect adjustment of said rotors in unison, means for maintaining fixed the angular position of said rotors with respect to each 10 other throughout their tuning adjustment in either direction, a counter weight associated with the rotor of one of said condensers, and abutment structure engaged by said counter weight for limiting the adjustment 16 of said rotors.

ARTHUR ATWATER KENT. 

